Add a test that BigInt does not have a parseInt function

test/built-ins/BigInt/parseInt/nonexistent.js

+// Copyright (C) 2017 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: BigInt does not have a static parseInt function
+features: [BigInt]
+---*/
+
+assert(!BigInt.hasOwnProperty("parseInt"));